A murine model of myeloma that allows genetic manipulation of the host microenvironment

Abstract

SUMMARY Multiple myeloma, and the associated osteolytic bone disease, is highly dependent upon cellular interactions within the bone marrow microenvironment. A major limitation of existing myeloma models is the requirement for a specific host strain of mouse, preventing molecular examination of the bone marrow microenvironment. The aim of the current study was to develop a model of myeloma in which the host microenvironment could be modified genetically. The Radl 5T murine model of myeloma is well characterized and closely mimics human myeloma. In the current study, we demonstrate 5T myeloma establishment in recombination activating gene 2 (RAG-2)-deficient mice, which have improper B- and T-cell development. Importantly, these mice can be easily bred with genetically modified mice to generate double knockout mice, allowing manipulation of the host microenvironment at a molecular level. Inoculation of 5TGM1 myeloma cells into RAG-2−/− mice resulted in myeloma development, which was associated with tumor growth within bone and an osteolytic bone disease, as assessed by microcomputed tomography (microCT), histology and histomorphometry. Myeloma-bearing RAG-2−/− mice displayed many features that were similar to both human myeloma and the original Radl 5T model. To demonstrate the use of this model, we have examined the effect of host-derived matrix metalloproteinase 9 (MMP-9) in the development of myeloma in vivo. Inoculation of 5TGM1 myeloma cells into mice that are deficient in RAG-2 and MMP-9 resulted in a reduction in both tumor burden and osteolytic bone disease when compared with RAG-2-deficient wild-type myeloma-bearing mice. The establishment of myeloma in RAG-2−/− mice permits molecular examination of the host contribution to myeloma pathogenesis in vivo.

Myeloma as a model for the process of metastasis: implications for therapy

“…MM cells were shown to constitutively produce MMP-9. 79,80 Similar results were observed with a VLA-4 (␣4␤1) inhibitory antibody 28 or with a selective antibody Natalizumab (Biogen Idec). 81 Similarly, P-selectin glycoprotein ligand-1 knockdown or inhibition by a small pan-selectin inhibitor (GMI-1070; Glycomimetics) showed significant inhibition of rolling and homing in vitro and in vivo.…”

Preclinical animal models of multiple myeloma

“…Recombinase-activating gene-2 (RAG-2)-immunodeficient mice on a C57BL/6 background have abnormal B-and T-cell development, resulting in a myelomapermissive environment. Fowler et al 23 demonstrated that inoculation of RAG-2-deficient mice with GFP-tagged 5TGM1 myeloma cells resulted in the same features of myeloma seen in the 5T Radl model, within a similar time frame of 4 weeks after inoculation and that, importantly, the RAG-2-deficient animals could be bred to genetically modified mice to improve investigators' ability to manipulate the host microenvironment. The immunodeficiency of the RAG-2-deficient mice, however, remains a disadvantage as compared with the immunocompetent 5T Radl model, as RAG-2 findings cannot be directly translated to the human microenvironment in myeloma development.…”

Multiple myeloma–derived MMP-13 mediates osteoclast fusogenesis and osteolytic disease

“…To assess the role of MMP-13 in the development of MM-associated bone disease in vivo, we next used an intratibial 5TGM1 murine model that recapitulates myeloma tumor growth coupled with severe osteolysis (41). To this end, GFP-expressing 5TGM1 cells were lentivirally transduced with EV control or 2 distinct shRNA expression vectors (Supplemental Figure 10C and refs.…”